Class StateEstimator

A state machine that performs state estimation, based on an input
stream of (input, output pairs) and a stochastic state-machine model.
The output at time t is a dist.DDist object, representing
the 'belief' distribution P(s | i_0, ... i_t, o_0, ..., o_t)

startState
The state of this machine is the same as its output: the
distribution over states of the subject machine given the input
sequence so far; the start state of this machine is the starting
distribution of the subject machine.